Research On Ecological Environment Assessment And Greening Design Of Fragile Road Areas

The highway construction brings many negative effects to the ecological system while it brings great benefit to human beings. Especially the highway construction in fragile or sensitive areas of ecological system is the focus of attention. Based on the cold climatic characteristics and a comprehensive survey in basic characteristics of ecological environment along the highway between Sui-Man road between Huangniuchang and Qiqihaer (Expressway) and Hengtoushan trunk highway (two grade tourism highway), the paper applies landscape ecology, community ecology, and restoration ecology theory, to put forward the concept of original ecological restoration; clarify the degree of interference from the soil of highway construction and operation on roadside vegetation; clear the road region ecosystem health; comprehensive evaluation; clear comprehensive evaluation of the road region ecosystem health; determine the high grade highway landscape design and landscape pattern. The results are as follows:1. The research of highway construction impacts on road areas soil shows that:transverse spatial distribution of soil heavy metals along the distance from the road farther, influence gradually reduce. The pollution and band width of Hengtoushan trunk highway is less than Sui-Man road between Huangniuchang and Qiqihaer. The relationship between soil surface variations of the vertical distance of each nutrient elements and highway shows that, in the natural soil, highway construction influence scope of natural soil nutrient quality uphill is0-100m, and downhill is0-200m; the effect is not strong on the regularity of the effect of artificial soil.2. The research of highway construction impacts on road areas vegetation shows that: from different ecosystem types, the accessibility of highway construction increases, and the natural ecological system is transformed into artificial ecosystem. From the ecological system, influence range of road to the plant structure is within200m. The basic performance of community structure index (the number ratio, the height ratio) is inverse relationship with distance to the highway. Influence along road of engineering type performs that different types have different effects, such as bridge engineering has great influence and the range of concentration, pavement engineering is a continuous process that fades away from the highway, interference source and interference intensity becomes small, and plant structure changes smaller; influence range communication mainly depends on the communication engineering construction scale. The change along the road plant community level structure indicates the heterogeneity of highway construction exacerbated the environmental factors, leading plant populations by uniform or random distribution transforming to the cluster type. 3. Through the study of plants resistance to heavy metals of road ecological restoration: the sequence of4representative of the common green plants (Syringa microphylla, Ligustrum obtusifolium, Swida alba, Salix purpurea) resistance to heavy metals:Swida alba> Salix purpurea> Ligustrum obtusifolium> Syringa microphylla.4. Comprehensively analyzing the impact factors of highway construction on road areas ecological health, comprehensive assesssment index system for road areas ecological health has been established; comprehensive assesssment model of road areas ecological health has been built which is based on analytic hierarchy process and fuzzy assesssment method whose build steps and derived formulas are also given; determining score calculation expression as the final assessment results; making Sui-Man road between Huangniuchang and Qiqihaer as an example to verify the assesssment system, the assessment results show that the integrated design, construction and operation of the project have fewer impacts on environment, but damages to the highway areas ecological environment have appeared in a certain degree, and the ecosystem service function and self-balance descend in a way, which can prove the validity and reliability of assessment system.5. Based on the above research, the landscape ecological aesthetics principle is applied in highway landscape design, in the case of Sui-Man road between Huangniuchang and Qiqihaer, analysis of the status quo conditions, and obtained the solution to problems. Starting from the angle of landscape design, transformed existing landscape, proposed detailed landscape mode. And in the case of Hengtoushan trunk highway, merged "Original ecology" landscape thought into landscape planning, proposed landscape nodes of plant species and greening mode of original ecological restoration, traditional way of sidewalk planting is abandoned, shurub and herbaceous plant is complementary seeding prerequisite to maintain present basement, a seasonal variations of plant landscape is formed accordingly, the ecological restoration technical program of road slope are presented.